3D Camera Transmittance Measurement Using Wavelength-Variable Light Source

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Solution Overview

Problem

Existing 3D cameras using the time-of-flight method face challenges in accurately measuring transmittance due to temperature variations affecting the transmission type shutter, leading to errors in estimating transmittance spectra without direct internal temperature measurement.

Innovation Solution

Incorporating a wavelength-variable light source that is thermally independent of the first light source and transmission type shutter, allowing for direct measurement of transmittance by emitting second light with varying wavelengths to align with the center wavelength of the shutter, and using a light blocker to prevent interference from the first light source.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a transmission type shutter is used to correct temperature effects on transmittance, then transmittance correction is improved, but measurement precision deteriorates because internal temperature cannot be directly measured

Engineering Contradiction:

Improvetransmittance correctionVSAvoidtemperature measurement

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

A second light source is introduced as an intermediary tool to measure the transmittance spectrum of the transmission type shutter. This light source emits light through the shutter while the shutter is in a state where the first light source is blocked, allowing direct measurement of the shutter's transmittance characteristics without relying on indirect temperature estimation.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If the first light source and transmission type shutter are operated together, then 3D imaging function is improved, but temperature variation increases affecting transmittance accuracy

Engineering Contradiction:

Improve3D imaging functionVSAvoidtemperature variation

Core Design Contradiction:

ProductivityVSTemperature

Solution Approach 1:

The system operates in periodic cycles: during normal 3D imaging operation the first light source and shutter work together, then during measurement phases the light blocker blocks the first light source while the second light source measures transmittance. This periodic switching allows both functions to coexist while minimizing temperature interference.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The measurement function is extracted from the normal imaging operation by using a separate second light source and timing the measurement when the first light source is blocked. This separation allows independent measurement of shutter transmittance without the thermal interference that occurs during active imaging.

Inventive Principle:

Principle #2Taking out (Extraction)

3Device complexity

If transmittance is estimated indirectly via internal temperature, then device complexity is reduced, but measurement precision deteriorates

Engineering Contradiction:

Improvemeasurement systemVSAvoidtransmittance measurement

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

A second light source serves as an intermediary measurement tool that directly probes the transmittance spectrum of the transmission type shutter. This approach maintains relatively simple device architecture while achieving high measurement precision by directly measuring light transmission through the shutter rather than inferring from temperature.

Inventive Principle:

Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution enables precise and direct measurement of transmittance, improving distance precision and demodulation efficiency by matching the wavelength of the first light with the center wavelength of the shutter, thus reducing errors caused by temperature changes.

Implementation Method 1

a transmission type shutter configured to modulate the reflected first light reflected to generate modulated light

Methodology Applied

Scientific EffectOptical modulation: Phase Modulation

Implementation Method 2

an image sensor configured to sense the modulated light that passes through the transmission type shutter

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Implementation Method 3

a second light source that is spaced apart from the first light source, the image sensor, and the transmission type shutter in order to be thermally unaffected... and is configured to emit second light toward the object, and to vary a wavelength of the second light

Methodology Applied

Scientific EffectWavelength tuning:

Data Source

PatentUS10362294B23D camera and method of measuring transmittance using the same

Publication Date: 2019.07.23 SAMSUNG ELECTRONICS CO LTD

AI summary

Provided are a three-dimensional (3D) camera including a wavelength-variable light source for directly measuring transmittance and a method of measuring the transmittance. The 3D camera includes, as well as a light source, a transmission type shutter, and an image sensor, and a wavelength-variable light source capable of irradiating a light with a variable wavelength without being thermally affected by the light source, the image sensor, and the transmission type shutter. The wavelength-variable light source may directly measure a change in transmittance by irradiating light toward the transmission type shutter while the 3D camera operates.